An arachnid version of the Jack-in-the-Box toy, California Trapdoor Spiders are not at all amusing to the prey they startle.

California Trapdoor Spiders are native to Southern California. In many ways, they resemble smaller versions of tarantulas, but with shiny, hairless bodies. The whole spider is black except for the rusty brown abdomen. The large, round cephalothorax has a deep dimple in the center of it. The chelicerae (jaws) have spines on them that help this species with digging underground burrows. As is the case with most spiders, the female California Trapdoor spider is larger than the male. Males search for females during the winter months. Females lay their fertilized eggs at the bottom of the burrow. Once spiderlings hatch, they leave the burrow, sometimes sooner rather than later thanks to heavy spring rains.

These burrows can be more than 7 or 8 inches deep and serve as both a home and a trap. The top of the burrow opening is covered with a silk door that is hinged. As the years pass, spiders add more silk webbing to their doors. They may also collect debris and loose leaf litter, helping to camouflage its existence. Burrows are usually built into hillsides or cliff-faces, often facing direct sunlight for ambient warmth and usually near vegetation that is likely to attract insects. Under this door, the spider waits and, when it senses oncoming prey, it quickly lunges out of its burrow and catches the prey item. Once caught, the prey gets pulled down into the trap and restrained in the burrow by both the spider's body as well as silk-covered walls inside the burrow. The prey is consumed below the door, leaving no warning above for future passersby.

Legs: Spiders have four pairs of legs and these are attached to the cephalothorax.

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Pedipalps: Small appendages near the mouth used as taste and smell organs.

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Cephalothorax: Contains eyes, head, mouthparts, and legs.

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Abdomen: Contains various organs related to digestion, reproduction, and web-making.

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Spinnerets: Used in the production of spider silk for fashioning webs or catching prey.

NOTE: Unlike insects, spiders have both an endoskeleton (internal) and exoskeleton (external).

Territorial Reach (A-to-Z)

Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed below as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections below indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.

The map below showcases (in red) the states and territories of North America where the California Trapdoor Spider may be found (but is not limited to). This sort of data can be useful in seeing concentrations of a particular species over the continent as well as revealing possible migratory patterns over a species' given lifespan. Some species are naturally confined by environment, weather, mating habits, food resources and the like while others see widespread expansion across most, or all, of North America.